Several experimental studies have reported that an otherwise robust regularity -the disparity between Willingness-To-Accept and Willingness-To-Pay -tends to be greatly reduced in repeated markets, posing a serious challenge to existing referencedependent and reference-independent models alike. This paper offers a new account of the evidence, based on the assumptions that individuals are affected by good and bad deals relative to the expected transaction price (price sensitivity), with bad deals having a larger impact on their utility ('bad-deal' aversion). These features of preferences explain the existing evidence better than alternative approaches, including the most recent developments of loss aversion models.Keywords: WTA/WTP disparity, price sensitivity, bad-deal aversion, Vickrey auctions, reference-dependence, loss aversion.
JEL classification: D11, D44 1The disparity between the Willingness-To-Accept (WTA) and Willingness-To-Pay (WTP) measures of value has been one of the most widely studied behavioural regularities in the last four decades. The disparity -which has been documented in a large number of contingent valuation and experimental studies 1 -poses serious challenges to Hicksian consumer theory and its applications to welfare economics.While in Hicksian consumer theory WTA and WTP can reasonably be expected to differ only by a few percentage points (Willig, 1976;Randall and Stoll, 1980) many studies have reported differences of much higher orders of magnitude. Such large disparities suggest that indifference curves are not reversible (Knetsch, 1989). They imply that the impact of policies that produce changes in resource allocation cannot be evaluated indifferently using the two measures, and that the resulting welfare changes cannot be approximated by changes in consumer's surplus. If improvements and deteriorations are regarded as highly asymmetrical, the Coase theorem no longer holds. Even in the absence of transaction costs and income effects, the outcome of a negotiation critically depends on the allocation of property rights. Yet, recently, several studies have found that the extent of the disparity is greatly reduced for experienced traders (List, 2003a(List, , 2004 and when agents repeatedly interact in experimental markets (e.g. Shogren et al., 2001;Loomes et al., 2003).Taken at face value, this whole body of evidence poses a theoretical puzzle.On the one hand, the existence and robustness of the disparity in one-off situations seems to indicate that preferences depart from the assumptions of standard consumer theory in systematic ways. This has led to the development of reference-dependent models that incorporate such departures (e.g. Tversky and Kahneman, 1991;Sugden, 2003;Köszegi and Rabin, 2006;Loomes et al., 2009). On the other hand, preferences elicited in experimental markets, in which subjects face feedback, repetition, and incentives, appear sometimes to be compatible with the properties generally assumed in reference-independent economic models. This paper offers a solu...